Clean water production calls for highly efficient and less energy-intensive technologies. Herein, a novel concept of a sequential ultrafiltration-catalysis membrane is developed by loading Co3O4/C@SiO2 yolk–shell nanoreactors into the fingerlike channels of a polymeric ultrafiltration membrane. Such a sequenced structure design successfully integrates selective separation with peroxymonosulfate-based catalysis to prepare a functionalized molecular sieve membrane, which exhibits excellent decontamination performance toward multipollutants by filtering the water matrices containing humic acid (HA) and bisphenol A (BPA). In this study, 100% rejection of HA and 95% catalytic degradation of BPA were achieved under a low pressure of 0.14 MPa and an ultrahigh flux of 229 L m–2 h–1, corresponding to a retention time of 3.1 s. Notably, the removal performance of multiple pollutants essentially depends on the ordered arrangement of ultrafiltration and catalysis. Moreover, the flow-through process demonstrated significant enhancement of BPA degradation kinetics, which is 21.9 times higher than that of a conventional batch reactor. This study provides a novel strategy for excellent removal of multiple pollutants in water.
The synthesis or decomposition of complex substances through the combination of metals and enzymes is desirable but still a huge challenge. A kind of yolk-shell structured Co/C@SiO 2 @Ni/C nanocomposites were prepared by the polyhedral ZIF-67@SiO 2 composite as a precursor through the extended stöber method and subsequent carbonization treatment. The SiO 2 as an intermediate protective layer stabilized the morphology and structure of the carbonized products. The metallic nickel nanoparticles were uniformly distributed on the surface of Co/C@SiO 2 @Ni/C for highly specific absorption of His-tagged organophosphohydrolase (OpdA) from cell lysates via affinity, and therefore an integrated nanocatalyst (INC) named OpdA@Co/C@SiO 2 @Ni/C was successfully prepared. The prepared INC was applied to achieve a one-pot chemoenzymatic cascade degradation of organophosphates (OPs) to p -aminophenol (PAP) within 30 min. In addition, the INC proved to be a simple and high-sensitivity nanocatalyst for the detection of methyl-parathion with a low limit of detection (0.30 μM). The INC exhibited improved pH stability, thermal stability, SDS resistance, and storage stability compared to that of free enzymes. When OpdA@Co/C@SiO 2 @Ni/C was reused for 7 cycles, the cascade degradation efficiency of methyl-parathion could retain more than 60 %. This study provides a strategy for constructing a multifunctional nanocatalyst, and further demonstrated its potential in biocatalysis, accurate detection of OPs and remediation of environmental pollution.
Jie Ding,Xiaodong Wu,Xiaodong Shen,Sheng Cui,Xiangbao Chen
In this work, palmitic acid (PA) is used as the PCM , while a novel kind of 3D porous carbon/silica composite aerogel (CSA) is involved as porous supporting material to prepare the form-stable PCM composites (PA/CSA). The carbon aerogel supported PCM composite (CA/PA) is provided as control. PCM infiltration mainly occurs for the large pores rather than micropores or mesopores. PA molecules are physically well combined with CA and CSA due to capillary force and surface tension. The addition of amorphous CA and CSA limits the crystalline growth of PA molecules. The CA/PA shows a separated and layered structure while the CSA/PA presents a CSA@PA core-shell structure with a rough surface due to large pores within the CSA pore matrix. The PCM loading mass fraction of CSA/PA (82.2%) is much larger than that of CA/PA (64.1%), and liquid leakage test indicates its excellent form-stabilization property. The melting point and melting latent heat of CA/PA sample is 39.73 °C and 96.27 J/g, respectively, while the melting latent heat of the CSA/PA sample is as high as 187.7 J/g. The CSA/PA possesses excellent thermal stability during cycling test and its short-term thermal insulation property has also been verified in this study.
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